Radio signaling system



July 27 1926.

. G. A. MATHIEU RADIO sicmmne sysmu FiledvMarch 10, 1922 Qwuenboz L PELG.A.MATH\EU @331 Qbfozmeng Patented July 27, 1926.

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GASTON ADELIN MATHIEU, OF LONDON, ENGLAND, ASSIG-NOR T0 RADIO CORPORA-TION OF AMERICA, A CORPORATION OF DELAWARE.

RADIO SIGNALING SYSTEM.

Application filed March 1-0, 1922, Serial No. 542,536, and in GreatBritain March 12, 1921.

According to this invention an oscillatory circuit is coupled either toan oscillatory circuit connected to the grid of the valve or to theanode filament circuit of the valve, the arrai'igement being such thatthe valve is normally on the point of oscillating but is unable to do soowing to the withdrawal of energy by the first named oscillatorycircuit. 0n the occurrence, however, of the small alternating currentsto be detected, say, on the arrival of wireless signals, the valveenabled to generate oscillations, but as soon as these. currents ceasethe valve ceases to oscillate. The currents in the anode circuit of thevalve are caused to affect the grid of a rectifying valve which has inits anode circuit a resistance the two ends of which are connected tothe grids of two other valves whose filaments are connected to themiddle point of this resistance while their anode circuits include thewinding of a relay. Gr the currents in the anode circuit of the firstvalve may be caused to affect one grid of a second valve having twogrids and the windings of the relay are then connected one in the anodecircuit of this valve and the other in the other grid filament circuitthereof.

The invention is illustrated by the accompanying drawing in which,

1 shows one arrangement conforming to the invention, and,

Fig. 52, shows a modification thereof.

in Fig. 1 A is the circuit in which flow the small currents to bedetected. B is an oscillatory circuit coupled thereto and to anos'icillatory circuit C connected to the grid and filament of valve Vthe anode circuit of which is coupled back to the circuit C so that thevalve can generate oscillations. lly adjusting a potentiometer lconnected across a biasing battery the suitable point on thecharacteristic of the valve may be found. For efficient working it isessential that the value of the back coupling should be. just sufficientto start and maintain oscillations in the circuit C. Owing, however, tothe withdrawal of energy by the circuit B the valve is normally unableto oscillate. /Vhen, however, energy is supplied to the circuit B fromthe circuit A on the occurrence of currents in the latter then the valvecan oscillate. As soon as the currents in A cease the valve will ceaseoscillating.

The currents the angel? llcuit of the valve V are led to a rectifyingvalve V so that a pulsating current flows in the anode circuit of thisvalve. The alternating component of this current finds an easy passagethrough a condenser 0 while the direct component causes a difference ofpotential between the ends of a resistance 1 The ends of this resistanceare connected to the grids of two valves V V the filaments of which areconnected to the middle of the resistance while in the anode circuits ofthese two valves are the windings D, D of a relay. The difference ofpotential at the ends of the resistance ll. causes both a positiveincrease of the grid potential of V and a negative increase of the gridpotential of the valve V This results in an increase in the anodecurrent of V which acts as the marking current, and in a decrease in theanode current of V which acts as the spacing current.

A condenser 0 may be connected across the relay in order to reduce theeffects of atmospherics.

If it is desired to have only a marking current in the relay, the valveV and the upper half of the resistance B may be omitted. Thisarrangement is particularly suit able for dealing with waves of a lengthbelow 2000 metres. For very short waves, say, those of a length below300 metres, the coupling between the anode and grid circuits of thevalve V may be capacitative instead of inductive.

Fig. 2 shows an'arrangement in which the circuit B is coupled not to thecircuits A and C which are directly coupled but to the anode circuit ofthe valve V and is connected to the filament and one grid G of a valve Vwhich has two grids, the other grid G being connected. to the winding Dof the relay while the winding D is connected to the anode of the valveV. As before, on the occurrence of currents in circuit A pulsatingcurrents will flow in the circuits of the anode and of the grid G of V.The direct component of the current in the anode circuit thereforeincreases and acts as the marking current while the direct component ofthe current absorbed by the grid G diminishes and acts as the spacingcurrent. The maximum strength of this spacing eurrent may be controlledby means of a battery E. Condensers c 0 in parallel with the windings ofthe relay allow the alternating components. of the urrents to p nd.

also serve for the passage of currents due to atmospherics.

Having described my invention, What I claim is:

1. In a relay arrangement, the combination of a source of smallalternating currents to be detected, a three electrode valve capable ofoscillating when said currents are supplied thereto, and an oscillatorycircuit arranged to Withdraw from the valve so much energy that thevalve is normally an able to oscillate and a rectifying valve coupled tothe output or the first valve and having a resistance in its outputcircuit and a relay connected across two points or the resistance.

2. In a relay arrangement, the combinaticn of a source of smallalternating currents to be detected, a three electrode valve capable ofoscillating when said currents are supplied thereto, and an oscillatorycircuit arranged to Withdraw from the valve so much energy that thevalve is normally unable to oscillate, a rectifying valve coupled to theoutput of the first valve and having a resistance shunted by a capacityin its output circuit and a relay connected across two points of theresistance.

3. In a relay arrangement, the combination of a source of smallalternating currents to be detected, a three electrode valve capable ofoscillating when said currents are supplied thereto, and an oscillatorycircuit arranged to ithdraw from the valve so much energy that the valveis normally unable to oscillate, a rectifying valve coupled to theoutput of the lirst valve and having a resistance in its output circuitand a pair of relays each connected to a mid point of the resistance andhaving the other connections at opposite sides of the mid point.

t. In a signaling system a circuit for the reception of smallalternating currents, a three electrode tube capable of starting andmaintaining self sustained oscillations and means independent of saidfirst named cir- 'cuit for Withdrawing from said tube suliicient energyto prevent it from generating oscillations in the absence of signalingcurrents in said first named circuit, said means comprising anoscillatory circuit.

In a signaling system a circuit for the reception oi small alternatingcurrents, a three electrode tube having an input circuit coupled 'tosaid first name-d circuit and an output circuit rege'neratively coupledto said input circuit said regenerative coupling being adjusted to avalue to start and main tain self sustained oscillations in said tubeand means independent of said first named circuit for 'i'vi'thdrawingsuflicient energy from said tube 'to prevent it from oscillating in theabsence of signals in said first named circuit said means comprising anoscillatory circuit coupled to one of said tube circuits.

6. in a signaling system a circuit for the reception of smallalternating currents, a three electrode tube having input and outputcircuits regeneratively coupled, the re generative coupling beingadjusted to a value to start and maintain self-sustained oscillations insaid tube and an oscillatory circuit inductively coupled to said firstnamed circuit and to said input circuit for absorbing suflicient energyfrom said tube to prevent it from oscillating in the absence of signalsin said first named circuit.

GASTON ADELIN MATHIEU.

